Animal litter and litter box system

ABSTRACT

A pelletized, environmentally friendly animal litter. The animal litter includes birch bark waste in pellet form that is mostly hydrophobic to allow liquid waste to quickly pass therethrough while trapping a small amount of waste therein that adheres to the surface of the pellet and is then absorbed over time. The litter is used in a litter box system that includes a base, a drawer slidably received therein for capturing waste in a preferred absorbent pad and a removeable grate suspended thereover for retaining the litter thereover. The drawer defines a container of sufficient volume to receive all of the litter when a standard amount of litter is used to fill the box which improves ease in changing litter by removing the grate and allowing the litter to drop into the drawer.

CROSS REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of U.S. Provisional PatentApplication Ser. No. 62/890,951 filed on Aug. 23, 2019, the disclosureof which is incorporated herein by reference.

TECHNICAL FIELD

The present disclosure pertains to animal litters for receiving animalwaste and box-type systems utilized to retain the litter whileinteracting with the waste as it is deposited by the animal. Moreparticularly, the present disclosure pertains to a pelletized cat littermade from natural, biodegradable and compostable materials and a catlitter box system that captures waste, reduces odor and improveshandling of the waste and spent cat litter by the cat owner.

BACKGROUND

Animal litter and containers for litter called litter boxes have allowedanimals, particularly cats, to reside inside owner's homes. However,many health and environmental issues have been identified with respectto materials and designs utilized for the litter and the litter boxsystem containing the litter. The current disclosure of a litter andlitter box system addresses the problems discussed below.

Many types of litter particulate are utilized with animal litter boxes,with most of them intended to absorb urine or other moisture anddecrease odor. Animals, such as cats and dogs, tend to use their paws tokick litter particles to cover their feces and urine. To help mimic thisnatural behavior, litter is frequently at a depth of 1 inch or more andis often loose and granular. Traditional litter has been clay-based catlitter which was introduced in the 1940's, and sodium bentonite, aclumping cat litter, was introduced in the 1980's. Clumpable littersclump together with liquid waste and can be sifted together for removalof the clumps containing the waste. This creates much dust, and oftenpieces of the clumps containing urine and feces break off and remain inthe litter box. Clay litters tend to be dusty, and frequently stick oncat's paws, and can be breathed by cats and their owners, along withbeing tracked all around their homes. Clay litters and dust may beingested when animals clean themselves. Further, clumping clay littercan contain chemicals such as sodium bentonite and crystalline silicawhich have been associated with health issues developed by breathing oringesting. Dust in cat litters can lead to respiratory problems in cats,especially kittens. Ingestion of these litters, or any non-biodegradablelitter, with moisture absorption can lead to blockages and dehydration.

According to the United States Geological Survey Mineral CommoditiesSummaries 2020, in the United States in 2019, 5.27 billion pounds ofbentonite clay and 4.32 billion pounds of Fullers Earth clay, for atotal of 9.59 billion pounds of clay was mined for pet waste litters,and since clay is not biodegradable, most of that ends up in landfillsas waste after use. Clay for litters is often strip mined, which isdestructive to the land and harmful to wildlife. Clays are also heavy totransport and carry, utilizing much energy to do so.

Some alternative litters have been developed. For example, silica gel,made with sand and mixed with water and oxygen, is another popularlitter material. It absorbs well, and lasts longer than clay litters,but it is another mined product, and therefore not sustainable, whileadding significantly also to landfill waste. There are also plant basedlitters that are easier on the environment, including litter made fromcorn, wheat, beet pulp, pine, and other plant materials. These are allmeant to absorb liquid excrement. The plant-based litters tend to bedusty and quite messy. They have granules that tend to stick to animal'spaws and fur and are tracked around a home. There are wood basedpellets, but they are designed to absorb liquid excrement and then fallapart when they get wet.

Because corn and wheat-based litters are edible, many animals will eatthe litter. Aflatoxins may grow on these litters in the moist urine andfeces environment that they are used. If transformed into mycotoxins,they could be deadly if ingested. Many litters have dust associated withthem, including clays, silicate, wood, corn, and walnut, and the dust isamplified with pouring it out of a container into the litter box, andwhen the animal paws and kicks to cover its solid waste. This can beunhealthy for animals and can cause respiratory problems for both theanimals and the people in the home.

Many litters also have added fragrances to mask bad odors associatedwith the liquid and solid waste in a litter box. Animals, particularlycats, are sensitive to many perfumes and deodorizers, which can causethem to avoid using their litter box, causing them to relieve themselvesoutside of the litter box. Cats urinating outside the litter box is thenumber one behavioral problem seen by veterinarians and the leadingcause of cats being relinquished to shelters. In addition to having alarge box, and avoiding fragrances, the latest research is showing thatthe most important factor in getting cats to consistently use theirlitter box, is to keep it clean.

Non-clumping non-water repellant litters also require frequent removalof the entire contents and cleaning of the box, which is wasteful, timeconsuming, and requires much maintenance. The clumpable litters requiredaily scooping, and need to be fully changed out less often, but littlepieces and chunks of litter containing urine and feces break off theclumps and contaminate the litter and do require full removal andcleaning of the box as they contribute to odor while retained in thelitter box.

Litters having some water repellant or pass through properties have beendisclosed, such as those in Matsuo, U.S. Pat. Nos. 8,230,811 and8,453,604, and Sogou U.S. Pat. No. 9,854,782. However, all the particlesdisclosed include inorganic porous material which must be mined ormanufactured and are not biodegradable. After use they are landfillwaste. Ikegami, in U.S. Pat. No. 7,387,075 discloses an animal litterthat has a water shedding portion and a liquid absorbing portion on eachlitter particulate, where the shedding part is treated with a waterrepellant finish, so the repellency is just on the outside surface, andnot throughout the litter particle.

In contrast to known animal litter, consumers are looking foralternative litters that are biodegradable, clay-free, silica-free,produce low dust, minimize tracking, have great odor control withoutfragrances, require minimal maintenance, and that are healthy and safefor cats, people and the planet.

In addition to animal litters, many types of litter boxes have beendisclosed in the art to improve the overall waste capturing and clean-upoperations. In Matsuo U.S. Pat. Nos. 6,994,054 and 7,131,396, the bottompart of the granular material container is detachable from the drippingcontainer for cleaning purposes, but their design does not allow removalwhile the litter is still in the container, nor does it allow a means ofdirecting of soiled litter into the reservoir formed by the drawer foreasy removal of soiled litter. Further, the design does not allow theability to change out the grate to allow different size grate openings.Many animals will accept a pellet litter, but others have more sensitivepaws, and require a softer and smaller particulate size. Other passthrough or filtering litter boxes, as in Matsuo, U.S. Pat. No.10,076,098, require the upper side cover, or in Matsuo U.S. Pat. No.9,888,666, require the upper container which holds the litter, and inMaguire U.S. Pat. No. 6,408,790, require that the whole littercontaining part needs to be lifted and removed and put down on anothersurface to be cleaned, or carried unhygienically with soiled litter, toa larger space for cleaning and disposing of the litter and for cleaningof the entire box. Having to fully remove the litter containing parts toclean a litter box exposes any area in contact with it to animalexcreta, is unhygienic, requires a large place and space to clean, andrequires carrying a dirty litter container to an area to clean it. Italso requires the carrying of a heavy, awkward, large container withsoiled litter. Some of the soiled litter and particles can also fallthrough the holes that are in the bottom of the litter container as itis being moved. Many houses and apartments do not have spaces to alloweasy, hygienic cleaning of a prior art litter box. Many people,particularly older seniors have difficulty lifting and carrying a heavy,large and awkward litter box.

In Matsuo U.S. Pat. No. 10,076,098, a pass-through litter box isdisclosed that includes a shallow tray having therein an absorbent pad.The pad includes a non-absorbent (Lc) flap of the pad that can come intocontact with the bottom wall of the side cover and become curled up. Toavoid this, the length of the side wall (Lb) in FIG. 14 , is to belarger than the length of the flaps. Due to this, it is difficult toshorten the fall length, as was their goal to decrease splattering ofdroplets. Their solution was to angle the tray side walls out toincrease the total area of the bottom and side walls footprint to belarger than the liquid passable region of their litter tray. With thetray inserted, the fall length is reduced, but the flap lengths don'tchange. The pad flap size is limited by side wall length, 15 mm. Whenthe absorbent portion of the pad is soiled, it's difficult to lift andcarry the saturated pad with small flaps. A user ends up touching theabsorbent portion of the soiled pad which is unsanitary and unpleasantand can also create leakage of liquid excrement when removing todispose.

Another identified problem with current animal litters, whether clay,cellulosic, grains, pellets, silica or any material, is that they tendto get stuck in animal's paws, tracking litter particles and dustoutside of the box creating a mess for the owner. The tracked litter anddust are unsanitary, malodorous, and can be gritty on surfaces all overthe house. Animals also ingest the litter and dust with their meticulousgrooming. Crystalline silica dust, a common ingredient in clumpinglitters, is a known carcinogen for both humans and household pets wheninhaled.

Numerous methods have been used to address animals tracking litteroutside the litter box. One approach is the use of various screens overbasins or trays to collect loose litter. These have either been not catfriendly or not easy to use. Another approach to prevent litter trackinginvolves animal litter boxes that have ramps built inside the litterbox. These can be difficult to clean and to keep clean. In U.S. Pat. No.6,386,143, they attempt to collect and recycle litter by use of multipleelongated raised surfaces sitting over a tray positioned in front of acat box entrance. In U.S. Pat. No. 8,181,601 it is disclosed to usesticky sheets to capture the litter from cats' paws, but cats avoidsticky surfaces. It fails to consider that cats have sensitive paws andwill avoid a surface that is not to their liking, by either avoidingusing the box and begin urinating and defecating outside of the box, orby jumping over the adverse surface.

In U.S. Pat. No. 6,983,720 they use louvered slats lined up to form aramp over a tray. Again, louvered slats are undesirable to cats. U.S.Pat. No. 8,181,601 has a ramp with fabric on it to clean the paws andfacilitate entering and exiting their specific cat box, but no means ofcatching any loose litter. Also, the ramp is only usable on their catbox. U.S. Pat. No. 5,992,350 has a tray that is underneath a cat boxthat can be pulled out, and a textured surface. This tray must be fullypulled out from under the cat box to be emptied, and does not direct theflow of loose litter to a place the cat would not step on again, socleaning of the surface would need to be done each time the cat exitedthe box, or else the cat could pick up the loose litter from the trayand track it outside of the tray.

None of the prior US patents attempts to resolve the problem of animalstracking soiled litter and dust outside of their box and cleaning theirpaws in a way that is easy to use, easy to clean, easy to return looselitter back into the litter box, and that captures the loose litter, islow cost, is adaptable to many different cat box styles, and pays greatattention to known cat and or animal preferences, and facilitatesentering and exiting the litter box so it can be accessed by animals ofall ages and physical abilities.

There is a great need and desire for an animal litter and litter boxsystem that overcomes the above deficiencies in the prior art. Inparticular, the system would maximize odor reduction, minimizemaintenance, clean easily, be healthy and safe for the animals using itand their human family members, and be environmentally friendly.

SUMMARY OF THE INVENTION

This disclosure provides design, material, manufacturing method, and usealternatives for an animal litter and litter box system. The inventionprovides an environmentally friendly animal litter and box system thatminimizes odor, mess, and maintenance, is hygienic and easy to clean, ishealthy and safe for animals, and allows health monitoring of urine. Thelitter box allows a means of cleaning so that it does not have to befully taken apart and/or carried unhygienically to another location tobe cleaned, decreases the frequency of changing out the litter and ofcleaning the whole system, and simplifies and makes the process ofremoving the soiled litter and cleaning the litter box more hygienic.

In one embodiment, the invention is an animal litter box system that canhave five major parts in some embodiments, including a bottom base witha solid flat bottom, a drawer/tray that slidably disposes within thebase and that may be used with, but may be used without, an absorbablepad to capture liquid excrement. The drawer glides into and out of thebase and a vertically seamless walled housing with three higher walls,and one anterior wall with a cut out opening for animal to go in andout. The housing is removably disposed over the base and engages via aperimeter flange. The housing has an open bottom that nests into thebase and the inside drawer upper front. There is a liquid permeableremovable grate removably disposed at the bottom of the housing thatencourages the flow of liquid waste therethrough but prevents thepassage of litter. The fifth element can be a ramp that attaches to thefront anterior wall cut out, that facilitates entering and exiting ofthe box, and captures litter particulate and cleaning an animal's pawsas they exit the box. The grate can cover the full width of the insideof the litter box to maximize walkable space for the animal and haverounded edges to facilitate liquid movement into reservoir drawer/trayand can easily be removed to pass the soiled litter into the reservoirdrawer to dispose of the litter hygienically. The volume defined by thedrawer is preferably greater than the volume of a standing filling ofthe litter box with a layer of litter up to 2.5 inches deep. Having aremovable grate also allows changing out the grate to allow varyingsizes of openings to allow various sizes of litter particulate.

The invention can include an animal litter used in a (filtering) litterbox which has superior odor control, requires much less maintenance asit lasts up to 30 days, is made with all-natural ingredients and is safefor animals, people and the planet. The animal litter is substantiallyhydrophobic, and a little hydrophilic. The animal litter is anall-natural, eco-friendly, biodegradable, sustainable, low dust,anti-tracking, naturally antibacterial and naturally anti-fungal,clay-free, silica free animal litter that decreases ammonia and filtersliquid excrement into a reservoir drawer that may be used with orwithout an eco-friendly pad to absorb the liquid waste.

In one embodiment, the litter is pelletized birch bark waste. The birchbark waste does not require the separation of inner and outer birchbark, has a high pass through or low sorbency rate, less than 25%, andpreferably a sorbency rate less than 10% as measured with a drip-test.Further, the pelletized birch bark waste has high dry durability,80-100%, preferred 95-99%, and low inhalable dust. Further, in aqualitative wet durability test, the birch bark waste pellets maintaintheir pellet shape or structure, in other words, even though they dohave some hydrophilicity, the pellet does not fall apart substantiallywhen wetted and a small portion of the liquid is absorbed. The birchbark waste pellets are mostly hydrophobic, so initially most liquidexcrement passes over the litter, through the grate, and into thereservoir drawer. Any remaining urine should be absorbed by the litter,(hydrophilic), and held in it so no remaining free urine is left in thelitter containing portion of the litter box to dry and create odor.

In some embodiments, the birch bark waste contains both birch bark andbole wood. The birch bark can be present in concentrations up to 90%,preferably about 50% to about 90%. The bole wood can be present inconcentrations from about 10% to 40%. In manufacturing the pellets, thepelletizing has a compression ratio of about 6:1 to about 9:1 in orderto create a preferred hydrophobic/hydrophilic surface on the pellets asdiscussed herein.

In some preferred embodiments the litter box system includes a wasteabsorbing pad that is retained within the drawer during use. Theabsorbent pad is for capturing liquid animal waste and can include awater impervious outer layer; a water permeable inner layer and at leastone middle layer including a fluff material having a super absorbentpolymer dispersed therethrough, wherein the inner and outer layers coverboth an outer perimeter of the pad and a central absorbing portion whilethe middle layer is absent from a portion of the outer perimeter. Thepad can further include retention means on the outer perimeter of thepad for retaining the position of the pad within a collection drawer ofan animal litter box. The retention means can be a drawstring slidablydisposed in a channel formed in the perimeter of the pad, four tabs onthe outer perimeter of the pad that releasably engage the over-runflange formed in the collection drawer of the animal litter box oralternatively C-shaped perforations extending from the outer perimeterof the pad to engage corners of the collection drawer of the animallitter box. Alternatively, the retention means can include a tautstretchy outer perimeter of the pad to go over the upper over-run flangeof the collection drawer. Each of these designs hold the absorbable padin position while moving the drawer in or out of the base.

The present disclosure can further include a ramp for ingress and egressfrom a litter box. The ramp can preferably contain two components, abottom outer base ramp and a ramp insert. The bottom base ramp has alower tray area for receiving the ramp insert, and an attachment andflap that engages the entrance edge of a litter box to retain a desiredposition for ingress and egress. The ramp insert nests into the insideof the bottom outer base ramp, has an upper surface which loosens litterfrom animal paws, and tapers toward the base ramp lower back railcreating an area to capture the loosened litter preventing it fromtracking outside of the ramp. An alternate embodiment has the rampinsert nested within the bottom base ramp and extending over a portionof its length so that loosened litter drops into the lower tray.

The above summary of some embodiments is not intended to describe eachdisclosed embodiment or every implementation of the present disclosure.The Figures, and Detailed Description, which follow, more particularlyexemplify these embodiments.

BRIEF DESCRIPTION OF THE DRAWINGS

The disclosure may be more completely understood in consideration of thefollowing detailed description in connection with the accompanyingdrawings, in which:

FIG. 1 is a perspective view of an embodiment of the animal litter boxaccording to present invention;

FIG. 2 is an exploded view of the embodiment of the animal litter boxaccording to FIG. 1 , depicting major components;

FIG. 3 is a perspective view of a base of animal litter box systemaccording to one embodiment;

FIG. 4 is an enlarged cross-sectional view of a portion of the base ofFIG. 3 along line C-C;

FIG. 5 is an enlarged cross-sectional view of a portion of the sidewalls along line G-G;

FIG. 6 is a perspective view of one embodiment of a drawer of thepresent invention;

FIG. 7 is an enlarged cross-sectional view of the drawer of FIG. 6showing the longitudinal cross section;

FIG. 8 is perspective view of an embodiment of a grate for receivingwaste there through;

FIG. 9A is an enlarged view of the surface of the grate of FIG. 8 ;

FIG. 9B is an enlarged cross-sectional view of the pass-through openingsin the grate of FIG. 8 ;

FIG. 10 is an enlarged cross-sectional view of a corner of the litterbox system showing the assembled relationship of the base, the grate andthe drawer along line A-A;

FIG. 11 is plan view depicting a continuous base and drawer enclosed bya retainment flange;

FIGS. 12A and B are an enlarged cross-section view depicting urineflowing through animal litter pellets and a grate;

FIG. 13 is a plan view of one embodiment of an absorbent pad;

FIG. 14 is an enlarged view of a drawstring through non-absorbent edgeof an absorbent pad;

FIG. 15 is a side view of an absorbent pad depicting multiple functionallayers;

FIG. 16A is a perspective view of an embodiment of a ramp;

FIG. 16B depicts the living hinge used to adjust the ramp;

FIG. 16C is a view of the ramp of FIG. 16A as attached to litter boxwith ramp emptying;

FIG. 16D is view of the ramp as positioned for use;

FIG. 17A is a perspective view of an alternate ramp;

FIG. 17B is a plan view of an alternate ramp insert for the ramp of FIG.17A;

FIG. 18 is a perspective view of an alternative embodiment of a drawerof the present invention;

FIG. 19 is a side view of the alternative drawer of FIG. 18 ;

FIG. 20 is a perspective view of an alternative embodiment of an animallitter box incorporating the drawer of FIG. 18 ;

FIG. 21 is a perspective view of the base in the animal litter box ofFIG. 20 ;

FIG. 22 is a perspective view of an alternative wall housing as includedin FIG. 20 ;

FIG. 23 is a perspective view of an alternative ramp;

FIG. 24 is a perspective view of the underside of the ramp of FIG. 23 ;and,

FIG. 25 is a perspective view of a ramp insert.

While the disclosure is amenable to various modifications andalternative forms, specifics thereof have been shown by way of examplein the drawings and will be described in detail. It should beunderstood, however, that the intention is not to limit the invention tothe particular embodiments described. On the contrary, the intention isto cover all modifications, equivalents, and alternatives falling withinthe spirit and scope of the disclosure.

DETAILED DESCRIPTION

For the following defined terms, these definitions shall be applied,unless a different definition is given in the claims or elsewhere inthis specification.

All numeric values are herein assumed to be modified by the term“about,” whether or not explicitly indicated. The term “about” generallyrefers to a range of numbers that one of skill in the art would considerequivalent to the recited value (i.e., having the same function orresult). In many instances, the terms “about” may include numbers thatare rounded to the nearest significant figure.

The recitation of numerical ranges by endpoints includes all numberswithin that range (e.g. 1 to 5 includes 1, 1.5, 2, 2.75, 3, 3.80, 4, and5).

As used in this specification and the appended claims, the singularforms “a”, “an”, and “the” include plural referents unless the contentclearly dictates otherwise. As used in this specification and theappended claims, the term “or” is generally employed in its senseincluding “and/or” unless the content clearly dictates otherwise.

It is noted that references in the specification to “an embodiment”,“some embodiments”, “other embodiments”, etc., indicate that theembodiment described may include one or more particular features,structures, and/or characteristics. However, such recitations do notnecessarily mean that all embodiments include the features, structures,and/or characteristics. Additionally, when features, structures, and/orcharacteristics are described in connection with one embodiment, itshould be understood that such features, structures, and/orcharacteristics may also be used in connection with other embodimentswhether explicitly described unless clearly stated to the contrary.

The following detailed description should be read with reference to thedrawings in which similar elements in different drawings are numberedthe same. The drawings, which are not necessarily to scale, depictillustrative embodiments and are not intended to limit the scope of theinvention.

The present invention relates to animal litter for all animals,including cats, dogs, rabbits, ferrets, horses, or any animal thatutilizes litter for urination and defecation. The litter is comprised ofingredients that are biodegradable, environmentally friendly,scent-free, minimize dust, minimize tracking, and minimize odor. Thelitter is designed to be used in some embodiments with a litter boxsystem with liquid passing through a grate and means of capturing liquidanimal excretions below the grate. The animal litter has primarilyliquid passing properties to transfer most of the liquid waste into thedrawer, with or without the use of an absorbent pad in the drawer. Anyremaining liquid waste is absorbed by the litter and held onto withinthe litter particulate, allowing use of litter for long periods of time,while minimizing odor.

The present invention relates to an animal litter system including ananimal litter box that can include a litter capturing ramp 160 (see FIG.16A), 172 (see FIG. 17A) or 182 (see FIG. 23 ), an animal litter 12 a,and a liquid waste absorbent pad 13 a. The animal litter box separatesout the liquid waste, and the animal litter particulate is selectivelymanufactured so it mostly repels the liquid waste, but it also absorbsany liquid waste that doesn't pass through to prevent odor formation.Therefore, the litter is mostly hydrophobic, but it also impartshydrophilic characteristics. The animal litter particulate is alsoenvironmentally friendly, biodegradable, non-toxic, has low dust, emitslow ammonia, is unscented, is lighter than clay litter, shaped tominimize animal tracking, and able to be put into a compost pile. Due tothe minimal absorption and minimal ammonia, the animal litter is longlasting, and healthy and safe for both animals and their caretakers. Itis naturally anti-fungal, antibacterial and anti-viral due totriterpenes present in the birch bark waste utilized. Further there isnatural hydrophobicity due to betulin in the birch bark.

The animal litter particulate matter of the present invention isdescribed below with preferred embodiments. As used here, “birch” is anyof the many deciduous trees of the genus Betula. The particulate matterused in the present invention is mainly composed of birch bark waste,which is a low value waste product in the forest industry. Birch barkwaste is generated when birch logs are debarked. Bole is the tree trunkfrom the ground to the crown break. The bole doesn't include majorbranches supporting the tree crown. Bole wood is the section of the bolethat is utilizable for a commercial product and is cut square at bothends to be made ready for delivery for processing. In the debarkingprocess, the wood that remains adhered to the bark is bole wood. Birchbark can be further divided into outer birch bark and inner birch bark.The process of separating the outer birch bark from the inner birch barkto make outer birch bark pellets to extract beneficial organic chemicalsis known and requires laborious work in the separation process, andcreates an expensive pellet that is cost prohibitive to use as an animallitter.

The present invention provides methods for producing a cost-efficientlitter and a process for a blended (both inner and outer birch bark andbole wood combined) birch bark litter pellet with mostly hydrophobiccharacteristics, but also with hydrophilic characteristics to beutilized with a pass-through animal litter box system.

Birch bark waste is obtained from a sawmill or paper mill. Depending ontime of year, the ratio of birch bark to bole wood can vary. A birchbark waste blend of 40-90% birch bark and 10-60% bole wood are theratios that are most common throughout the year, with winter having ahigher bole wood content due to freezing and less ease of debarking thetree. A preferred embodiment uses a ratio of 50-80% birch bark to 20-50%bole wood to produce the best animal litter pellet. A lower birch barkcontent creates too much liquid absorption and not enough liquid passthrough. With less birch bark, there is less hydrophobicity, andtherefore more hydrophilicity. With more hydrophilicity, the litterparticulate can break apart faster, and not last as long.

One or more materials may be utilized as additions to the birch barkwaste in some embodiment, such as other hardwood or softwood tree barkwaste, including, but not limited to aspen, pine, fir and maple barkwaste, the outside of fruit, nuts, rice, seeds, including but notlimited to shells, hulls, husks, agricultural products (coffee chaff,sunflower hulls, wild rice hulls, pistachio shells, safflower hulls),and other pulverized wood materials may be combined with the birch barkwaste to make the animal litter.

The litter particulate matter produced for the present invention may beformed by a disk pelletizer, a briquette machine, a tableting machine orsimilar. In one embodiment, the preferred method is the disk pelletizerdue to availability and price. Ideal pre-pelleting or forming moisturelevels range from 12-15% prior to entering the pellet die, or other.However, the wood industry seldom uses steam to maintain final pelletmoisture at a minimum. Steam is only utilized to start pelleting ifmoisture content is below ideal ranges. If steam is required, use a highpressure 46 Kw (5 HP) Chromalox electric steam boiler, or similar, witha set pressure of 65 psi (high pressure).

Prior to grinding, the birch bark waste may need to be dried if moisturecontent is too high. Birch bark waste may be air dried or dried in amachine known in the art such as a rotating dryer. Final moisture of theproduct is in a range from 6-13% and preferred in the 8-11% range.

When the animal litter particulate is formed into a cylindrical pelletshape, the average diameter range is from 3-8 mm, and preferably 4-7 mm.The average individual particulate length is 3-30 mm, and preferably6-10 mm. An animal such as a cat prefers small litter particulate, butif the particulate is too small it tends to get caught in the animal'spaws and creates tracking of the litter particulate around the house.Also, the litter particulate needs to be large enough to not fallthrough or get stuck in between the bars of the grate. An advantage of aremovable grate is that you can have different litter particulate sizeswith different grate open space sizes between bars.

It is preferable that the amount of water absorbed in a water sorbencydrip-test is in the range of 0.01-0.20 water absorbed/product used (g/g)or 1% to 20%. In the sorbency drip-test, a lower sorbency numberindicates a lower affinity to attract and absorb water. This means thatmore liquid waste is repelled from the litter particulate, and thereforethe litter lasts longer as there is less particulate deformation, lessparticulate disintegration, and less odor.

The sorbency can be measured with the sorbency drip-test method whichfocuses on exposure time, density, and sorbent ability. Pelleted litteris weighed and placed into a cylinder. Then 100 grams of water is pouredthrough the cylinder and pass-through water is collected after 5 minutesand weighed. Product sorbency is a calculation of water retained dividedby the starting mass.

The preferred pellet durability is above 90%, and more preferred to beabove 98%. With lower particulate durability, the litter particulate maybreak down with distribution, or with animals walking on them, and itmay shorten length of time the litter is able to be used.

The durability is measured using the Kansas State University PelletDurability Index Score (PDI). The test measures the durability of a drypellet before being exposed to moisture, such as cat urine in use.Durability of pellets should be determined by tumbling the test samplefor 10 minutes at 50 r.p.m. in a dust-tight enclosure, starting with aconsistent weight of pellets, and starting immediately after cooling.When the temperature of the pellets is within ±10 degrees)(° Fahrenheitof ambient, they are considered cool. The device is rotated around anaxis that is perpendicular to and centered in the 12 inch sides. A 2inch by 9 inch plate is affixed symmetrically along one of its 9 inchsides to a diagonal of one 12 inch by 12 inch side of the can. A doormay be placed on any side and should be dust-proof. Projections, such asrivets and screws, should be kept to a minimum and well rounded.

A sample of pellets to be tested should be sieved on the appropriatesieve to remove all fines. Fines shall be determined by screening asample on a wire sieve having openings just smaller than the nominalpellet diameter. If pellets of 0.5 inch diameter or larger are beingtested, select pellets that are between 1.25 inches and 1.5 inches long.Place a 500-gram sample of sieved pellets in the tumbling can device.After tumbling for 10 minutes, the sample will be removed, sieved, andthe percent of whole pellets calculated. Pellet durability is definedas: Durability=weight of pellets after tumbling (g) divided by weight ofpellets before tumbling (500 g)×100.

Inhalable dust is currently classified as dust particles less than 10micron. Peak dust is the highest recorded concentration of dust lessthan or equal to 10 microns during a test period. Concentration valuesare stated as milligrams per cubic meter. The preferred least amount ofinhalable dust is less than 10 milligrams per cubic meter. Forrespiratory health of both the animals and the humans residing in theanimals' house, the least amount of dust is most desirable. NationalOptical Astronomy Observatory states that the risk of particulateexposure for entering the respiratory system can be determined by thelength of exposure, concentrations, and most importantly, the size ofthe dust particle.

To evaluate the level of inhalable dust generated through handling ofmaterial, a DustTrak® monitor is utilized to filter and read dustconcentrations utilizing light scattering technology. For eachindividual test, a 100 gram sample is evaluated. Sample is analyzed forinhalable dust less than 10 microns. Document current temperature andhumidity. Use a 32 inch collectively in total drop tube height, and acollection box. Drop litter down the tube and into a collection box. Thesample and dust generated are captured in a box at the bottom of thetube with an air outlet port at the side of the box. Test utilizing a 10micron filter.

It is preferable that as small of an amount of ammonia NH3 be generatedas possible, less than or equal to 0.1 ppm at 1 hour and 24 hours afterexposure. Measure a level of ammonia generated on litter particulateusing a Drager tester. The procedure to evaluate ammonia control ofanimal litter particulate is as follows.

1. Fill a 250 ml plastic measuring cup with two test litters. Littershould be added to reach a level that is 1 inch below the top of therim.

2. Test liquid utilized is four parts water with one part 5% ammoniahydroxide or household ammonia (4:1). This level of ammonia is utilizedto serve as an “index”. For performance and should provide a detectablelevel for comparison. Synthetic urine contains only 1.0 E-4 percent (%)ammonia, producing very limited levels of ammonia for performancetesting.

3. Using a pipe tote, add 5 ml of solution to each cup.

4. Wait 1 hour.

5. Document room temperature and humidity.

6. Using the Drager tester with the 5-30 ppm tubes, test each litter anddocument NH3 levels obtained.

7. Repeat steps 1-3 and wait 24 hours. Then repeat steps 5-6.

A preferred method of manufacturing by pelletizing of the animal litteris described. Moisture content range of the birch bark waste should befrom 12-15%.

Prior to pelleting, the birch bark waste product is ground using a 25HP, 22-inch Champion brand hammer mill rotating at 3,600 r.p.m. With a3/16-inch hole screen for the first pass followed by a ⅛- 1/16-inchscreen for the second pass.

Pellet die size utilized for production for a preferred embodimentincluded a 6:1 compression ratio CR (compression ratio=die length/holediameter) to a 9:1 compression ratio CR, with a die diameter of 3 mm-7mm. A thicker die with a greater compression ratio produces a productwith improved performance. Pelleting for the trial was conducted on a60-Hp California Pellet Mill. The pellet mill runs using 220V/3 phaseelectricity. Operating idle amperage is 16 A and full load amperage is70 A.

In a first representative litter that was manufactured, the presentinvention is a pelletized animal litter particulate and method ofproduction as described in detail below. Birch bark waste comprised of80% birch bark and 20% bole wood were utilized. Initial startingmoisture content was 13.5%. Prior to pelleting, the birch bark wasteproduct was ground using a 25 HP, 22-inch Champion brand hammer millrotating at 3,600 r.p.m., with a 3/16 inch hole screen for the firstpass followed by a ⅛ inch screen for the second pass. Pellet die sizeutilized for production for a preferred embodiment included a 6:1compression ratio CR (compression ratio=die length/hole diameter). Thedie diameter was ¼ inch. A thicker die with a greater compression ratioproduces a product with improved performance. In particular, it has beenfound that the compression ratio impacts the durability of the pelletsin a wet test. This is a qualitative test in which pellets are placed ina liquid for a period of time. After such time, the pellets are observedto determine if they retain their pellet shape and defined exteriorsurface. This quality is both a function of the compression ratio andthe materials used. As it is desirable to have some hydrophilicity asstated above, there is some liquid absorbed into the pellets on each useby the animal. If the pellet breaks down when wetted, it will not lastin the litter box and become problematic from many perspectives.Therefore, it is preferred that pellets of the present invention havethe previously stated sorbency range while substantially maintainingpellet form over the period of use between litter changes. Pelleting forthe trial was conducted on a 60 HP California Pellet Mill. The pelletmill runs using 220V/3 phase electricity. Operating idle amperage is 16A and full load amperage is 70 A.

The animal litter of a second representative litter that wasmanufactured followed the same methods as the first representativelitter, except that the compression ratio included a 7:1 compressionratio. The die diameter was ¼ inch.

In a third representative litter that was manufactured, the same methodsof the first representative litter were followed, except that the birchbark composition was 60% birch bark, and bole wood was 40%. Thecompression ratio was 8:1, with a ¼ inch die width.

Properties of the three representative litters that were manufacturedwere tested along with comparing properties under the same tests for acommercially available litter sold under the Tidy Cats® Breeze® labeland a generic clay pellet litter. The results of these tests arepresented in Tables 1, 2 and 3 below. The superior properties of pelletsof the present invention are evident, especially the secondrepresentative sample.

TABLE 1 Pellet Water Pellet Die Durability Absorbed/Product Final PelletProduct Utilized (%) Used (g/g) Moisture (%) First Preferred Embodiment:¼ in × 6:1 CR 95.8% 0.19 10.2% 80% birch bark/20% bolewood SecondPreferred Embodiment: ¼ in × 7:1 CR 98.5% 0.09 9.3% 80% birch bark/20%bolewood Third Preferred Embodiment: ¼ in × 8:1 CR 97.9% 0.13 9.3% 60%birch bark/20% bolewood

TABLE 2 Peak Dust Concentration Product Peak 10 micron First PreferredEmbodiment 6.1 80/20. 6:1 CR Second Preferred Embodiment 6.7 80/20. 7:1CR Third Preferred Embodiment 5.8 60/40. 8:1 Tidy Cats Breeze 18.3 TidyCats 24/7 (prilled) 27 Clay Granulated Litter 150

TABLE 3 Ammonia Level Ammonia Level Product at 1 hour (ppm) at 24 hours(ppm) Second Preferred Embodiment 0 0 80% birch bark/20% bolewood TidyCats Breeze Pellet 0.45 0

The animal litter of a fourth embodiment was the same as above in allthree embodiments, and then adding either into the ground mix, or byspraying in after pelletizing, a bio-based odor neutralizer such as butnot limited to Itaconix® ZINADOR™ 22L, which is an odor neutralizingchemical that is a polymeric zinc itaconate complex that is 100%bio-based.

Another alternative embodiment would be same as above and add anotherone or two organic ingredients into the ground mixture, such as but notlimited to hulls or shells of nuts, seeds, fruit, or grasses.

As shown in FIGS. 1-2 , an overall perspective view of an animal litterbox according to the present invention is depicted with drawer 3 in theinserted or closed position, and configured to have main components ofbase 1, on the bottom with 3 sided flange; wall 2, with 4 vertical sidewalls and bottom flange which rests on base and drawer totally enclosedretainment flange, 8 (see FIG. 11 ); with drawer 3 to house absorbentpad 13 a (see FIG. 13 ) or liquid waste, which when inserted to properposition resides underneath the grate 4; Grate 4, which supports litterparticulate, litter particulate 12 a (see FIG. 12 ), and ramps 160 (seeFIGS. 16A, 16B and 16D) and 172 (see FIG. 17A) which attach to wall 2. Apredetermined amount of liquid repellent litter is dispersed over thegrate 4 to a preferred depth. The liquid absorbing pad 13 a (see FIG. 13) resides within the drawer. An alternative embodiment is to not use aliquid absorbing pad within the drawer.

FIGS. 20-22 depict an alternative embodiment of the above litter boxhaving a different flange design but incorporating the same functionalfeatures. Drawer 3A is in the inserted or closed position and configuredto have main components of base 1A, on the bottom with a 4-sidedcontinuous flange to couple to the housing.

Base 1 is a rectangular shaped bottom part with continuous 3-sided baseflange 1 p to set the positioning of wall 2 and to guide drawer 3 tosmoothly glide in and out of base 1 and to house drawer 3 when drawer 3is in the inserted or closed position. As shown in FIGS. 3-6 the upperinterior edge of the continuous 3 sided base flange 1 p is retainmentflange 1 b, which along with first vertical flange 1 c and top femalefillet 1 f, have shared surfaces with wall 2 external surface retainmentflange 2 cd, and sets the positioning of the wall 2 by trapping it on 3sides, 1 transverse, and 2 longitudinal. Fillet if goes into the secondhorizontal flange 1 d and a second vertical flange 1 e moving downwardat an angle of about 1°. At the external shared surface of the wall 2,both female fillets if and 1 m are filleting at about 0.18 inches forthe ease of cleaning with 1 fingertip. From the bottom female fillet 1m, a male fillet 1 n is formed inward and downward approximately 0.25inches to a shared surface with the drawer 3, the overrun flange 3 e.This shared surface directs, controls, and prevents lateral motion ofthe drawer as it glides into the put-in position in the base 1, or forremoval of the drawer 3 from the base 1 put-in position, preventingspillage of liquid waste within the drawer 3. The solid surface bottom 1a captures any liquid waste that may spill out of drawer preventingliquid waste from spilling on surfaces outside of the animal litter box10.

Alternative embodiments of the above litter box system are depicted inFIGS. 18-22 . The alternative system provides the same function as abovebut includes slightly modified components that assemble together. Inparticular, base 1A is a rectangular shaped bottom part with acontinuous 4-sided base flange. The flange receives the housing walls 2Awhile the entire opening for drawer 3A is formed in the base rather thanby part of the housing front wall. The upper interior edge of thecontinuous 4-sided base flange 1 pp, is retainment flange 1 bb, whichhave shared surfaces with wall 2A, external surface retainment flange 2cd, and set the positioning of the wall 2A by trapping it on four sides.

Shown in FIGS. 3 and 4 , the base 1 has 5 bosses, which are slightlyhigher than the floor of the base 1 a. The 4 circular boss's 1 k, arefor indexing and permanent placement of rubber bump-ons to prevent theanimal litter box 10 from moving or scratching a surface it may beresting on. The 5th ramped boss 1 j creates a large flat surface planeramped for the drawer 3 to glide smoothly as moving into and out of base1 put-in position, with the largest elevation toward the posterior wallof base, and gradually decreasing height as moving to the open side ofbase. The bosses 1 k and 1 j also create a gap above the drawer 3 asdrawer is removed from base 1, preventing jamming between the drawer andthe flange of the wall 2. An alternative embodiment may have some ornone of the bosses on base 1 and/or 1A.

Shown in FIGS. 1, 2, 5, and 10 , wall 2, and in FIGS. 20-22 as wall 2A,have a total of four side walls 2 a and 2 aa, with one of the side walls2 aa, which could be on short side wall as in preferred embodiment, oralternate embodiment cut-out could be on long side wall, with cut-outfor animal entering and exiting animal litter box 10. Wall 2 has aseries of flanges directed inward that externally nests with a fullyenclosed continuous retainment flange 8 (see FIG. 11 ) made up of threesides of base 1 and one side of drawer 3 or alternatively made up offour sides of base 1A.

As shown in FIGS. 1-7 , several embodiments show the drawer 3 openingand deboss drawer pull 3 b and doorway opening 5 on a short side wall ofanimal litter box, but deboss drawer pull 3 b and drawer opening anddoorway opening 5 could also be located on a long side wall of animallitter box. Alternatively, FIGS. 18 and 19 show that drawer 3A can havea bottom deboss handle 3 bb.

As shown in FIGS. 5 and 10 , from the lower portion of wall 2 verticalside wall 2 a, the first horizontal flange 2 c moves inward (about 0.55inches), and downward (about 0.15 inches) to form a 15° loft. The firsthorizontal flange 2 c, then becomes vertical flange 2 d, which extrudesdownward about 0.25 inches at an angle of 1°. The external surface ofthese two flanges, first horizontal flange 2 c and vertical flange 2 d,form retainment flange 2 cd, and have a shared surface with base 1internal surface of base retainment flange 1 b and first vertical flange1 c. On the edge of the intersection of vertical side wall 2 a, andfirst horizontal flange 2 c, is fillet 2 b, sized appropriately at thechosen part material thickness such that the resulting interior fillet 2b is sized relatively close to 0.25 inches for the ease of cleaning with1 finger. The interior function of retainment flange 2 cd is to houseand seat grate 4. From vertical flange 2 d, second horizontal flange 2 egoes inward at about 0.5 inches and downward at about 0.13 inchescreating another 15° loft. The final horizontal flange 2 f movesdownward about 0.25 inches, 30° from the split plane and terminates atthe intersection of final horizontal flange 2 f with the interior wallof drawer 2 i. The horizontal surfaces being drafted at or above 15°prevents puddling and then drying of liquid waste which preventsmalodor. The increase of the final flange angle from 15 to 30° is toaccelerate liquid waste flow toward drawer 2, to prevent the liquidwaste from drying or adhering to the animal litter box 10. The trimmededge 2 g is cut in a direction perpendicular to the split plane toaccelerate liquid waste flow preventing it from working its way back outof the drawer 2.

The surround walls of housing 2 or 2A, are seamless, so there is noleakage of liquid waste through a seam, and no cover required. Animals,such as male cats and dogs tend to urinate high and may urinate outsideof a litter box if the litter box doesn't have high sides. As animalscan urinate at multiple angles, urine can leak out through the seambetween a cover and a side wall, or any sidewall seams. Animal litterboxes 10 and 10A has no side wall seams and prevents liquid wasteleakage outside of animal litter box 10 and 10A.

In some embodiments, the litter box includes a removable grate withdivot cut-outs on short or long ends of the grate. In Matsuo U.S. Pat.Nos. 6,994,054 and 7,131,396, the bottom part of the litter drawer isdetachable from the dripping container for cleaning purposes, but theirdesign does not allow removal while the litter is still in thecontainer, nor does it allow a means of directing of soiled litter intothe reservoir drawer for easy removal of soiled litter. The presentdisclosed grate is removable, while litter is on the grate, by using thedivot cut-out to lift with a finger, or to use litter scoop, and liftingas gliding the grate backwards, directing soiled litter into drawer.Further, the design allows the ability to change out the grate to allowdifferent size grate openings, allowing various litter particulate sizesand to increase ease of cleaning the box. The varying styles of gratesimproves the versatility of the system. Many animals will accept apellet litter, but others have more sensitive paws, and require a softerand smaller particulate size.

As shown in FIGS. 1, 8, and 10 , the grate is a rigid and strong liquidpermeable removable grate 4 with a plurality of openings to maximize thepassage of liquid waste, while preventing the passage of litter. Thegrate 4 spans the entire transverse width and longitudinal length of theinside of the wall 2 vertical side walls 2 a and 2 aa, creating a largesurface/footprint area for the animal to move around in within thelitter box 10. The grate 4 openings need to have enough open area tofacilitate the passing of liquid waste through them, and enough strengthto prevent deformation of the grate bars 4 b due to the weight of theanimal and the litter particulate. To maximize the pass through ofliquid waste, the grate 4 has a 25-75% open area, preferably 45-60%,strong enough to support the weight of at minimum of 20 pounds, morepreferably 25-30 pounds; the weight of the litter plus the weight of ananimal.

Grate deformation causes litter particulate to get caught in between thegrate bars 4 b and could create deformation movement which is startlingto an animal and could dissuade an animal from using the animal litterbox 10 or 10A. A strong grate 4 material, such as an ABS plastic orstainless steel, but not limited to these materials, is preferred, toprevent deformation. Grate 4 rounded bars 4 b on top and bottom surfacesfacilitates a hydrophobicity by having curves and no flat surfaces, tomaximize liquid waste pass through.

All grate surfaces that may be contacted by animal urine are smooth androunded to maximize liquid waste flow from the top of the grate, overthe rounded bars 4 b, through the liquid permeable open spaces, to flowto the bottom side of the grate 4 and then to flow away from the bottomside of the grate bar 4 b creating a stream of liquid encouraging flow,and avoiding droplets which splatter. The rounded surfaces of the gratebars 4 b also create a mildly uneven upper surface so litter particulateis uneven, which creates space between litter particulate, facilitatingquick and efficient movement of fluid through litter particulate,through the top side of grate through to the bottom side of grate 4 todrawer 3 or 3A. Projections 4 c on outside edge 4 e of grate 4, preventtranslational or longitudinal movement of ramp when ramp is set in wallretainment flange 2 cd, while also creating a small space between thewall retainment flange 2 cd and the outside edge 4 f of the grate 4. Theprojections 4 c also extend slightly superiorly and inferiorly beyondthe height of the edge on both the top and bottom sides of the edge,creating a load onto the projections 4 c and slightly elevating grate 4,creating a space between the bottom of the edge 4 f creating a pathwayfor any liquid to flow from the side wall 2 a, fillet 2 b, firsthorizontal flange 2 c, wall retainment flange 2 cd, vertical flange 2 d,second horizontal flange 2 e, final horizontal flange 2 f, over thetrimmed edge 2 g, and into the drawer 4. An alternative embodiment forthe grate is a mildly textured grate with subtle bumps and valleys, or awoven wire mesh that angles inferiorly to the lowest (valley) area.Liquid, such as urine from an animal, is excreted onto the litterparticulate 12 a (see FIG. 12 ), passes through the litter particulate12 a, the grate 4 and into the drawer 3 or 3A, which may or may not usean absorbent pad within the drawer.

In at least some preferred embodiments the drawer is a deep reservoirwith a top rolled edged that can hold all the litter when it is desiredto empty the litter from the box by removing the grate. The deepreservoir drawer with top edge rolled outward and enlarged in thecorners 3 p in FIG. 18 , allows easy pouring out of captured liquidexcrement. When using without a pad, the box is designed to allow easyremoval of the reservoir drawer, carrying the drawer with urine todispose of liquid waste without spilling, and easy pouring into atoilet. This also allows ease of accessing animal urine for healthtesting of the animal. It is possible to measure total urine output andallow easy use of the urine for urinalysis for diagnosing disease, orfor screening for health problems. The pads offer convenience and reduceodor and are utilized in preferred embodiments. The drawer gives theconsumer the option to use a pad or not use a pad, or to easilyalternate. The catch basin/liquid reservoir drawer has a larger volumethan previous litter boxes, and can hold 6-9 cups of liquid, or 12+ cupsof litter allowing less frequent emptying, and less maintenance.Further, less pads are needed if they are large capacity pads. If aperson chooses to use the pad, the pad will capture, retain the urine,and neutralize the odor.

As shown in FIGS. 1, 2 & 6 , the removable drawer 3, receives and holdsthe liquid waste that has been excreted from an animal. The drawer has abottom 3 c, which at each side wall creates a 0.4-inch fillet 3 g,intended for easy cleaning. This fillet 3 g connects into the 4 verticalside walls 3 d, and moving upward at the top edge, forms into theover-run flange 3 e. The 2 longer sidewalls run longitudinal and areopposite from each other. The 2 shorter side walls run transverse andare across from each other.

In drawer 3, the front over-run flange 3 e then connects into the frontinterior flange 3 n. The interior flange connects into the continuousexterior surface of the drawer 3 a. A plane, perpendicular to the floor,parallel with the transverse width of the animal litter box 10, andcoincident at the intersection of the large exterior fillets 3 h and theflat edge running the depth, creates the joint between the interiorflange edge 3 l and the exterior edge 3 i surface, and the flat flangesurface 11, the intersection of drawer exterior edge and base flatflange surface 6, in FIG. 1 . This creates a clean aesthetic andfunctional transition between two separate components of the animallitter box 10.

In the alternative, drawer 3A of FIGS. 18 and 19 , the front over-runflange 3 e then forms an outer small male fillet 3 q, and then extendsvertically downward 3 r, to a horizontal connection 3 s, into thevertical 3 t drawer handle 3 bb. The space 3 u, creates a retainmentarea for the outer edge of the absorbable pad for all four sides of thedrawer over-run flanges 3 e. When the drawer 3A is in the inserted orclosed position of the base 1A, a joint is created along the horizontaltop edge of the handle 3 v, the two vertical sidewalls 3 w of thehandle, and the base interior opening edges, creating a clean aestheticand functional transition between the two separate components of theanimal litter box 10A.

FIG. 11 shows the totally enclosed retainment flange 8, created bycombining the base 1 and the drawer 3 when the drawer is in the fullyclosed or put-in position. FIGS. 2, 5, and 11 demonstrate how thisretainment flange creates a seating for wall 2 external flange 2 h.

In animal litter box 10, there are eight total cuts, called cinchnotches 3 f; two in each of the four corners of the drawer. These cinchnotches 3 f allow the absorbent pad 13 a to attach to the drawer 3, sothe pad remains in position and does not get caught up when moving thedrawer in or out of the put-in position or totally closed position.

A preferred embodiment is for the drawer to house an absorbent pad 13 ato capture and hold onto the liquid waste and to neutralize odors. Anabsorbable pad made to lay flat on the bottom of a reservoir drawer, togo up the sides of the reservoir drawer, and to bend outward over theover-run edges 3 n of the reservoir drawer. The outer non-absorbentedges may have perforated handle “C” cut outs. An alternative embodimentis a drawstring in the outer peripheral border of non-absorbing portionof pad that runs through a channel made from the bottom impermeablelayer by folding over and sealing. The drawstring lays flat within thechannel until ready to be pulled out and cinched. The drawstring is madeof similar bottom impermeable material. There are two exits for thedrawstring from the channel, directly across from each other, preferablyfront and back, but could be side and side. Once the pad is saturated,the border is lifted over the edge, and the drawstring is pulled fromthe two exit areas as lifting and cinching, keeping all the urine andsaturated pad contents locked in, allowing easy, clean disposal withoutspilling, or touching the saturated areas. It can then be carried tocomposter or garbage. An alternative to the drawstring is: two-fourhandled perforated cut out handle areas, ideally one for each side ofthe outer impermeable layer but could be two opposite sides. An optionproximal to the cut-out handle, on the back/outside of impermeablelayer, would be an attachment of impermeable plastic, attached in themiddle to the impermeable layer, and shaped as width and length allowingto tie around the four pad edges where the perforated handles arebrought together. This again would prevent touching of the soiledportions of the pad, and prevent any spillage of contents, and alloweasy transport to dispose of pad. Another embodiment of the absorbentpad would have C-shaped perforations in the corners of the outernon-absorbing portions of the pad edges extending in the corners fromthe outer perimenter of the pad to engage the drawer retainment flange 3m or the enlarged over-run edge corners 3 p of the drawer 3A of theanimal litter box 10 or 10A, or alternatively, a taut stretchy outerperimeter of the non-absorbing outer edge of the pad to go over theupper angled over-run edges 3 e of the collection drawer, to hold theabsorbable pad in position while moving the drawer in or out of thebase.

In preferred embodiments, the absorbable pad has multiple layers. Thetop layer is a liquid permeable sheet, preferably made from bamboo or awood fiber; the bottom layer is liquid impermeable and made of aplant-based bioplastic that is biodegradable or compostable such aspolylactic acid. Between is an absorbent non-woven fluff layer,preferable bamboo or wood fiber, a biodegradable super absorbent polymer(SAP), starch-based SAP that is biodegradable or preferably acompostable SAP. Alternative embodiments include a hydrophilic clumpablecat litter substrate to assist with absorption, retainment of liquid,and neutralization of urine for odor control. There may be abiodegradable substance added for management of odor, or odorneutralization.

The absorbable portion is sized to fit in bottom of drawer, and toppermeable and bottom non-permeable layer to continue up the verticalside walls. In each corner there can be two cinch notches for the cornerof the permeable/non-permeable portion of the pad to pinch into.Removing the grate with the soiled litter in the litter tray and havingthe bottom edge of base to direct the litter particulate, allows litterto passively drop into reservoir drawer, making changing litter quick,easy and hygienic, significantly reducing required maintenance. No needto take the whole system apart to clean the box; just empty used litterinto reservoir drawer, spray & wipe smooth inner walls and grate withwipeable cleaner, replace grate, replace clean reservoir drawer, and addfresh litter. The reservoir drawer with soiled litter can easily beemptied into a bag or container to be disposed of, or easily be carriedto an area to dispose of or be composted. All the cleaning can takeplace without having to move a dirty litter container with holes orhauling whole system to a cleaning area. Our litter drawer is deep withhigher sides, and large bottom surface, allowing the dirty litter tostay in the tray to be easily carried with clean outer surface, and tocontain dirty litter, and dispose with ease. Litter drawer is muchsmaller, lighter and easier to carry than the whole litter container.

When using absorbent pad, the absorbent portion of the pad fits on theinside bottom of the reservoir container. The non-absorbent bottom layerand top layer combine and continue outward beyond the absorbent layer,and angles upward along the reservoir drawer walls, and goes up and overhorizontal top edge. In a preferred embodiment the non-absorbent edgecontinues up all four side walls and has tabs 13 e that slide into eachcinch notch—2 at each corner, to hold onto pad edge. This edge may ormay not have a drawstring/cinch to facilitate removal in a clean andeasy way, or may have “C” shaped tabs in each corner. Undo tabs fromcinch notch areas in each corner and simply lift each corner of padedge. If it has a drawstring, each corner drawstring will be pulled,tightening up the whole pad, with all the absorbent portion of pad withliquid contents, locked into a bag made with pad. Another option is tohave “C” shaped perforations in the sides of the non-absorbent portionof pad, and use those to lift pad, again keeping absorbent portion ofpad contained inside to prevent leaking and to prevent touching theliquid waste. In one embodiment, the pads edge goes laterally over thetray lateral edge and then inferiorly and to follow outside wall. Inanother embodiment, the widened edge goes over the tray edge, andcontains a drawstring or cinch, within a tunnel made by folding over thebottom impermeable edge of the absorbent pad outward and sealing. Thisprevents the non-absorbent edge, or flaps, of the pad from gettingcaught and curling up, on the bottom of the lower edge of the side wallas it is being pushed back into the base. Another preferred embodimentof the absorbable pads outer non-absorbent edge would have C-shapedperforations in the corners of the outer non-absorbing portions of thepad extending in the corners from the outer perimeter of the pad toengage the drawer retainment flange 3 m or the enlarged over-run edgecorners 3 p of the drawer 3A of the animal litter box 10 or 10A.Alternatively, the pad could have a taut stretchy outer perimeter of thenon-absorbing outer edge of the pad to go over the upper over-run edges3 e of the collection drawer to hold the abosorbable pad in positionwhile moving the drawer in or out of the base.

FIG. 13 depicts the absorbent pad 13 a that may be used to captureliquid waste in the drawer 3. The absorbent pad 13 a is made with allbio-based components and is therefore biodegradable. 13 b is theabsorbent portion of the pad and 13 c is the non-absorbent portion wherethe perforated handles 13 d are located. Tab 13 e is the location thatthe non-absorbent portion of the pad that fits into on the cinch notches3 e on the drawer 3. These cinch notches 3 e hold the pad down and makeit tight so that it doesn't get caught up as the drawer 3 moves in andout.

FIG. 15 shows the layers of the absorbable portion of the absorbent pad13 a. The top layer is a liquid permeable top sheet that is hydrophilicand pulls the liquid in and disperses the liquid waste. The second layeris fluff or wood pulp, or bamboo fluff or nesting material that is alsohydrophilic and pulls the liquid waste in. Next is a biodegradablestarch-based super absorbent polymer material (SAP) that isenvironmentally friendly. The 4th layer is another non-woven permeablelayer that disperses the liquid so that as much of the liquid waste aspossible contacts the biodegradable SAP. The bottom layer is abioplastic impermeable membrane material. This prevents animal liquidwaste from leaking out of the pad. All the components are biodegradable,and environmentally safe for the planet.

Another possible component to add into the absorbable pad is a bio-basedodor neutralizer such as Itaconix® ZINADOR™ 22L, which is a polymericzinc itaconate complex that is 100% bio-based. It is also possible toadd additional ingredients to the absorbent pad, including changingorder of layers and numbers of layers.

The absorbent portion 13 b of the pad is in the center rectangle seeFIG. 13 . The non-absorbent border 13 c is a continuation of the topsheet 15 a and the bottom sheet 15 e. In a preferred embodiment, theabsorbent portion 13 b lays on the floor of the drawer FIG. 6, 3 c, andthe non-absorbent border 13 c rests against the inner side walls of thedrawer. The drawer has two cinch notches 3 f in each of the 4 corners,for the non-absorbent corner tabs 13 e of the pad to push into andtighten the pad down. This directs the edge of the nonabsorbent portionover the over-run flange 3 e to keep the nonabsorbent portion 13 c tightagainst the drawer side wall 3 d and over-run flange edge 3 e,preventing the side walls from falling inward away from the side wall 3d, and preventing liquid waste from getting behind and underneath thebottom layer of the absorbable pad 13 a. On each of the fournon-absorbent borders is a perforated 13 d area that becomes a handle.This becomes a handle when removing the soiled and saturated pad fromthe drawer.

In a second preferred embodiment, the non-absorbent portion of theabsorbent pad 13 a, continues out over the drawer over-run flange 3 e,and contains a drawstring or cinch see FIG. 14, 14 a, within a tunnelmade by folding over the 14 b bottom impermeable edge of the absorbentpad outward and sealing the edge. The cinch notches 3 f would again beused as in first preferred embodiment. In removing the soiled andsaturated absorbent pad from the drawer, remove the cinchednon-absorbent pad tabs 13 e first, and then as in FIG. 14 , lift each ofthe four drawstrings 14 a and 14 b on each of the four sides of thenon-absorbent pad 13 c areas in a similar location as the perforatedhandles 13 d. Lifting the four drawstrings 14 a and 14 b, tightens upthe whole absorbent pad 13 a, keeping all of the soiled and saturatedcontents locked in. This makes clean, easy, and sanitary removal of allliquid waste, reducing the maintenance and mess with what can be anunpleasant task. The alternative designs for the pad also provide thisbenefit.

Because the soiled absorbent pad contains all biodegradable components,urine and pad materials, this pad can be put into a compost bin. Usingbio-based materials decreases the environmental impact from a materialsside to the end disposal side.

Use of the absorbent pad 13 a significantly reduces the maintenancerequired in keeping an animal litter box clean. The pad 13 a capturesand holds onto the liquid waste and can decrease the frequency of havingto remove the liquid waste, whether through a clumpable litter, orthrough use with animal litter box 10 or 10A, without using theabsorbent pad 13 a. The absorbent pad 13 a as described above shouldlast up to 5-9 days for one cat, of average weight of 9-10 pounds, whichproduces an average of ½ cup of urine daily. The absorbent pad 13 aholds onto the urine and neutralizes the odor, preventing malodorousodors from being released into the air. The liquid absorbent sheet 13 aallows less maintenance with decrease changing of the pad to every 5-9days for one animal, clean and easy removal and disposal of pad.

The present invention comprises a lightweight ramp with outer base trayand inner ramp insert that attaches to most styles of litter boxes, thatcleans animal's paws, that captures litter tracked outside a litter box,that facilitates entering and exiting the litter box for all animals,allows cat scratching on the insert, is easy to use, has a low cost, andkeeps animals' preferences in mind.

As shown in the drawings, the present invention comprises a rampassembly that can include a lightweight bottom base ramp tray with siderails and a back rail, and may have a front flap (if made out ofcorrugated cardboard), or with an inferior angled projection flap ifmade of a solid material, that attaches to most styles of litter boxeswhich would go over the front edge of a litter box, which captures andholds the litter, along with a lightweight rigid insert ramp, whichloosens and cleans the animals paws as it walks down the ramp onexiting. The top insert ramp may end prior to the bottom base ramp tray,or can have a tapered end creating a holding area for captured loosenedand tracked litter, until ready to put back into the litter box 10 or10A. The base ramp tray and inner ramp nest and attach to the edge of ananimal litter box, to facilitate the ingress and egress from the box foranimals of all ages and abilities, including kittens, senior cats, andcats with mobility problems. The ramp is easy for cats, animals andtheir owners to use, easy to clean, easy to capture and return looselitter back into the box, is low cost, and keeps animal preferences inmind. To return the litter to the litter box, you just lift and pour itback into the litter box.

One preferred embodiment would include the base tray of corrugatedcardboard, which could be sprayed with a wax to add liquid resistance,with the front flap adjustable to the varied inside edge of a litterbox. By being approximately 3 inches, the lower tray flap is held inplace by the upper insert rigid ramp. The upper insert ramp could becorrugated cardboard and nest with the tray. The base tray ramp couldalso be made from a material such as, but not limited to: wood, bamboo,or plywood, and a top walking surface with a material such as, but notlimited to corrugated cardboard, sisal, seagrass, hemp, or jute.

Another preferred embodiment would include the base tray made out of asolid material such as, but not limited to wood, bamboo, compressedpaper, plastic or plywood, and bent to an angle of 90 to 125° or in oneembodiment approximately a 115° angle, and the nesting ramp made out ofcorrugated cardboard or a material such as, but not limited to wood,bamboo, plastic or plywood with a top walking surface such as, but notlimited to sisal, seagrass, hemp, or jute. If the base tray is made outof material other than cardboard, the front angle flap would measure 90to 125° or preferably around 115°, with the top ramp being eithercorrugated, and in that case a rigid angle of 90 to 125° or preferablyapproximately 115° to nest with the firm tray, or if wood, bamboo,compressed paper plastic or plywood, it would be bent to the sameangle/nesting, and the top walking surface could be attached to the topramp by Velcro, or an adhesive, or by staples or other attachments.

Another embodiment of the outer tray could be a compressed paper productwhich resists moisture. A light spray of wax could be sprayed on thetray to add moisture resistance to the tray.

Another preferred embodiment would be a ramp that is made out on thesame material as the animal litter box described and attaches to thefront opening of the wall portion of the animal litter box.

The animal litter box 10 has an alternative embodiment that includes theuse of a ramp to capture tracked litter, to clean paws, and tofacilitate entering and exiting the animal litter box 10. FIGS. 16 a, 16b, 16 c, and 16 d , shows one preferred embodiment that is designedspecifically for use with animal litter box 10. As shown in FIGS. 16 a,16 b, 16 c, and 16 d , the ramp 160 is attachable and detachable byincluding a living hinge 167. On each side of the living hinge is afemale attachment, the litter box attachment 168, and the rampattachment, 169. The ramp 160 itself has two vertical longitudinal sidewalls 161 that can vary in size and shape, that corral the animal andencourage the animal to use the ramp getting in and out of the litterbox, one vertical transverse back wall 163, a bottom 165, and a rampinsert reservoir 170 that accepts and retains a ramp insert 171. Theramp insert 170 is rectangular and can be made of various materials thatare acceptable to animal's paws including, but not limited to corrugatedcardboard or a sea grass carpet.

From the top inside edge of the vertical side walls 161 moving down, thesurface takes a 90° bend inward and another 90° bend downward creating anarrow insert border 162 to meet the bottom 165. Animals tend to tracklitter and dust out of the litter box. The ramps 160 and 172 aredesigned to clean the animal's paws, and to loosen and capture anylitter and dust. The litter collects at the end of the ramp in the catchspace. As demonstrated in FIG. 16C, empty the captured litter from outof the ramp and back into the litter box by lifting the end of the rampwith the handle 164, and pouring litter back into litter box. Then lowerramp back down.

An alternate embodiment of ramp 160 is the same ramp as above, however,the vertical side walls 161 continue straight down from the top edge andmeet the bottom 165 at 90° with a small fillet to facilitate easycleaning, and the side walls 161 become one with the ramp insertreservoir walls. There is no insert border 102 in this secondembodiment.

FIGS. 23-25 depict another alternative embodiment of a ramp for use withand made of the same materials as litter boxes 10 and 10A. The ramp 182has 2 vertical sidewalls 188, one vertical backwall 189, and an angledshort front wall 185 that goes up to a flat edge 186. FIG. 25 shows theramp insert 184, which resides within the bottom of ramp 182, as shownin FIG. 23 . The insert 184 has 2 longitudinal flat edges 190 thatcontact the inside of the ramp 182 sidewalls 188 and an angled frontedge 191, that will contact and be retained by the angled front wall185, and a tapered end 192 creating space for captured litter. FIG. 23shows the attachment flap 187, which lays over the vertical front wall 2aa of the litter box 10 or 10A. This allows easy attachment of the ramp187 to litter box 10 or 10A and easy removal of the ramp 187 to allowemptying of captured litter back into the litter box. The insert may beremovably attached to the bottom of the ramp using an adhesive.

Another preferred embodiment of the animal litter box 10 and 10Aincludes ramp 172 shown in FIGS. 17A and 17B. This embodiment is usefulfor any litter box with an 8 inch or greater opening for animalsentering or exiting, and rests on the edge of the litter box withoutusing a living hinge. It has 2 parts, including the lightweight outertray 173 and the inner ramp 177. The outer tray 173 has 2 side walls 174and back wall 175 and a bottom. In this example, the outer tray, 173,has front moveable flap 176 that can adapt to whichever angle isrequired for resting on a litter box entrance edge. The rigid inner ramp177 has a 115° angle bend 181, and nests by resting on top of the outertray 173. The front edge of the inner ramp 177, nests over the tray flap176, which rests over the entrance edge of a litter box. Thisfacilitates the ingress and egress from the litter box of animals of allages and abilities, including kittens, senior cats, and cats withmobility problems. The outer tray 173 can be made with multiplematerials including but not limited to corrugated cardboard, wood,plywood, compressed paper and compressed wood. The inner ramp 177 couldalso be made with multiple materials including, but not limited tocorrugated cardboard, compressed paper, compressed wood, seagrass,sisal, hemp or jute.

Another example of the ramp 172 is an outer tray 173 made out if a solidmaterial such as, but not limited to wood, bamboo, or plywood,compressed paper, plastic or wood, and bent to an angle of preferablyapproximately 115°, or a range of 90° to 125°, and the nesting innerramp 177 could be made out of corrugated cardboard, a material such asbut not limited to wood, bamboo, plywood, compressed paper or wood andsisal, seagrass, hemp or jute. If the outer tray 173 is a material otherthan corrugated, the front angle flap 176 would measure preferably about115°, with a range of 90° to 125°, and the inner ramp 177 would be bentto the same angle to allow a nesting of the two parts. The top surfaceof the inner ramp 177 may be attached using Velcro, adhesives, staples,or other. If the outer tray is made of corrugated or compressed paper,it may be sprayed with a light spray of wax to add moisture resistance.

What is claimed is:
 1. A pelletized animal litter comprising birch barkwaste, the birch bark waste including a mixture of about 50% to about90% birch bark, including both inner and outer birch bark, and about 10%to about 60% birch bole wood.
 2. The pelletized animal litter of claim1, wherein a concentration of birch bark is between about 60% to about90%.
 3. The pelletized animal litter of claim 1, wherein a concentrationof bole wood is between about 10% and about 40%.
 4. The pelletizedanimal litter of claim 1, wherein a pelletizing compression ratio of theanimal litter is about 6:1 to 9:1.
 5. The pelletized animal litter ofclaim 4, wherein a durability of the animal litter is greater than 90%.6. The pelletized animal litter of claim 5, wherein a sorbency of theanimal litter is less than 25%.
 7. The pelletized animal litter of claim6, wherein an inhalable dust concentration of the animal litter is lessthan 10 mg/m³.
 8. A litter box system for use with an animal litter, thelitter box system comprising: a bottom base; a drawer that slidablydisposes within the bottom base, and which glides into and out of thebottom base, the drawer having a reservoir; a walled housing with atleast three walls, and a front anterior wall with a cut out opening foran animal to go in and out which is removably disposed over the bottombase and engages via a perimeter flange wherein the walled housing hasan open bottom that nests into the bottom base and an upper front of thedrawer; a liquid permeable removable grate disposed within the walledhousing, wherein the grate encourages the flow of liquid wastetherethrough but prevents the passage of litter disposed thereon; andpelletized litter disposed on the removable grate, the pelletized littercomprising birch bark waste, the birch bark waste including a mixture ofabout 50% to about 90% birch bark, including both inner and outer birchbark, and about 10% to about 60% birch bole wood.
 9. The litter boxsystem of claim 8, further comprising a ramp that attaches to the frontanterior wall cut out and facilitates entering and exiting of the boxwhile capturing litter particulate and cleaning an animal's paws as theyexit the box.
 10. The litter box system of claim 8, wherein the grateincludes rounded edges to facilitate liquid movement into the reservoirof the drawer.
 11. The litter box system of claim 8, wherein the grateincludes divots so it can be easily removed to pass the soiled litterinto the reservoir of the drawer to dispose of the litter hygienically.12. The litter box system of claim 11, wherein a volume defined by thedrawer is greater than or equal to a volume of litter used in a standardlitter box.
 13. The pelletized animal litter of claim 1, wherein themixture is ratio of 50% to 80% birch bark and 20% to 50% birch bolewood.
 14. The pelletized animal litter of claim 1, further comprisingone or more of hulls or shells of nuts, seeds, fruit, or grasses. 15.The pelletized animal litter of claim 14, wherein the hulls or shells ofnuts, seeds, fruit, or grasses include one or more of coffee chaff,sunflower hulls, wild rice hulls, pistachio shells, and safflower hulls.16. The pelletized animal litter of claim 1, further comprising otherhardwood or softwood tree bark waste from one or more of aspen, pine,fir, or maple trees.
 17. The pelletized animal litter of claim 1,wherein the mixture is a ratio of 60% birch bark and 40% birch bolewood.
 18. The pelletized animal litter of claim 1, wherein a finalpellet moisture concentration is 8% to 11%.